Lifting device



March 26, 1963 L. s. BILLMAN LIFTING DEVICE 2 Sheets-Sheet l Filed Deo. 5, 1960 Flax March 26, 1963 L. s. BILLMAN 3,082,836

LIFTING DEVICE INVENTOR I OLJIS S Ell-LMAN Y B ATTORNEY United States Patent Glice 3,082,836 Patented Mar. 26, 1963 3,032,836 LIFTING DEVICE Louis S. Hillman, Glastonbury, Coun., assigner to United Aircraft Corporation, East Hartford, Conn., a corporation of Delaware Filed Dec. 5, 1960, Ser. No. 73,744 6 Claims. (Cl. 180-7) This invention relates to lifting devices and more particularly to air or gas operated lifting mechanisms.

It is an object of this invention to provide a lifting device which responds to a fluid under pressure to raise substantially heavy objects, while at the same time providing for itself a controlled air cushion whereby the object lifted and the lifting device can be readily moved around with a minimum of human effort.

Thus, with a lifting device of this type it is an object of this invention to provide a relatively simple, inexpensive telescopic mechanism which forms a supporting platform to lift heavy objects and which responds to very little side forces whereby it can readily be moved from one location to another along a given surface.

These and other objects of this invention willbecome readily apparent from the following detailed description of the drawing in which:

FIG. l is a cross section of a typical device with the parts in the inactive position and resting on the ground;

FIG. 2 is similar to FIG. 1 with the parts in the active or lifting position;

FIG. 3 is a modiiied version of the device including a varied seal arrangement;

FIG. 4 is a partial cross section of a modified arrangement of the device illustrating a specific valve and seal arrangement;

FIG. 5 is another modified arrangement -of the device shown in cross section; and

FG. 6 is a section taken along the line 6-6 of FIG. 5.

Referring to FIG. l, a lifting device is generally indicated at 10 as having an outer cylindrical member 12 which has a cooperating piston-like element "14 mounted in telescoping relationship therewith. The outer cylinder 12 includes an upper body-supporting platform or cover 16 upon which may rest a suitable object or mass which is to be lifted. 'I'he piston-like member 14 includes a number of seals 18 mounted on the outer periphery thereof to prevent the flow of any uid between the mating surfaces of the cylinder 12 and the piston 14.

The piston 14 includes a transverse wall 20 which in cooperation with the cylinder 12 forms an upper chamber 22 and a lower chamber 24.

The upper closure wall or supporting surface 16 has fixed thereto an upper valve portion 30 which slides within a cooperating valve sleeve 32 carried by the transverse wall 20 of the piston 14. The valve element 30 includes a drilled passage 34 which communicates at its upper end via a port 36 to a line 38 which extends through the side wall of the cylinder 12. The line 38 carries a coupling 48 which connects a pipe 42 leading to a suitable force of liuid under pressure. The iluid under pressure may come from a suitable shop air pressure line or a compressor or from a compressed gas tank which would readily be carried by the cylinder 12. The valve element 30 also includes a lower annular port 46 which cooperates with a port 4S carried by the valve sleeve element 32. Thus, it is apparent that depending on the relative position of the valve elements 30 and 32 the alignment of ports `46 and 48 will present a larger or smaller passage for an outflow of uid into the upper chamber 22.

When air or a suitable gas under pressure is supplied through the supply line 42 and the passage 38, it will readily ow through the drilled passage 34 and the passages 46 and 48 so as to raise the pressure in the chamber 22. As the pressure in the chamber 22 increases, the cylinder 12 will rise to the position shown in FIG. 2. This motion will raise the particular object to be lifted and at the same time will move the ports 46 and 48 of the valve elements 30` and 32 respectively to the position shown in FIG. 2 thereby limiting the height to which the cylinder 12 can be raised. As the cylinder 12 is raised, air pressure will continue to act in an upward direction on closure wall 16, while also acting in a downward direction on the transverse wall 20 of the piston element 14. However, the force acting downward on the wall 20 is adjusted to be just sufficient to keep the seal member 54 in engagement with the ground surface 56. This is accomplished by providing one or more bleed passages 58 in the wall 20` so that a predetermined pressure drop occurs across the passage 58 and hence there is a slight difference of pressure between the chambers 22 and 24. Thus there will be a force acting up on the wall 20, but such a force will be less than that in the chamber 22. In this way, although a great amount of force is available to lift the cylinder 12 and any object carried thereby, there is also a force acting down on the piston 14 and the wall 28 but just enough to maintain the seal 54 in contact with the ground or oor. There will, of course, be a little leakage past the bottom of the seal, but this will be made up for by re-adjustment of the valve elements 30 and 32 and subsequent flow to the bleed passage 58.

In FIGS. l and 2 the seal 54 is shown as a simple bunch of brush bristles which are closely compacted and surround a center core of Teflon sheet material to present a resisting wall for air passage but are still eXible enough to provide continuous contact to the ground surface in spite of small irregularities therein.

As seen in FIG. 3, a somewhat modified arrangement is illustrated. Thus the same structure of the cylinder 12, as well as the valve elements 30 and 32, are retained but piston 14a carries a suitable flexible annular seal 18a which has one end thereof fixed at 70` to the cylinder 12 and at its other end 72 to the piston 14a. The seal at its bottom end includes an annular ground-engaging element 74 which is circular in section and may be filled with a suitable soft spongelike material 76. Thus the seal 74 can readily deflect to accommodate irregularities on the surface upon which it is resting.

FIG. 4 is another modification of this invention which is adapted for low proiile devices. Thus the inlet line may be fixed -to the cylinder 82 and include a passage 84. This forms an inner valve 86 which cooperates with an outer valve element 88 which is loaded by a line spring 90 into engagement with a cam 92. The cam 92 forms one end of an arcuate link 94 which is pivoted immediate its ends at 96. The other end 98 of the link 94 engages the top of the transverse wall 10i) of a piston 102. A flexible seal 164 may be utilized in much the same manner as illustrated in FIG. 3. However, the port wall engaging portion 106 of the seal forms an annular exible chamber 188. A small pas-sage 110 leading from the upper pressure passage 112 will cause an inflation of the seal end 166 as soon as pressure is supplied through the line 80. Thus the pressure in the chamber 188 will always be proportionally higher than the pressure in lower chamber 114 due to the pressure drop across the bleed 116.

FIG. 5 shows another modification of this basic concept whereby an outer cylinder is provided with an inner piston 132 including a suitable annular seal 134 between the cooperating walls of the cylinder and the piston. In this instance the cylinder 130 carries a pipe 133 and a valve seat 135. A valve element 136 cooperates with the seat 135 and is carried by a stem 138 fixed to a transverse web 140 carried by the piston 132, In this case since the pressure in chamber 142 and 144 will be the same, one or more springs 15) and 152 may be provided to force the piston 132 in a downward direction whereby the seals 154 engage the supporting wall with just sufricient force to minimize leakage.

As a result of this invention it will be apparent that a very simple lifting device has been provided which can raise or lower relatively heavy objects while at the same time can automatically provide a supporting cushion whereby the entire device including the raised object can be easily pushed around on a factory `floor or in a warehouse.

Further, a device of this sort can utilize any form of gas under pressure either from a central supply source or from a portable tank carried by the device itself. It is visualized that with extremely simple and cheap devices of this sort, they can be built as an integral part of large containers which must be constantly transported or moved around while in use. Thus large oil drums, beverage kegs, or other large containers might have built integral therewith inexpensive lifting devices of this sort whereby they can be raised and given considerable mobility in that they can be moved with little human effort.

Although several embodiments of this invention have been illustrated and described herein, it will be apparent that various changes and modiiications can be made in the construction and arrangement of the various parts without departing from the scope of this novel concept.

What is desired by Letters Patent is:

l. A lifting device including first and second cylindrical members, said members being positioned in telescopic relation, said iirst cylindrical member including a top closure wall and thereby forming a closed chamber which is open at the bottom, seal means carried by one of said members and cooperating with the other of -said members to prevent leakage therebetween, said second cylindrical member including a lower portion engaging a supporting surface, said second member being also open to said supporting surface, pressure means between said members for urging said members apart, means for conducting said pressure means into said chamber, valve means included in said conducting means and having an opening, means operatively connected to said valve means and reponsive to the relative position of said members for varying said opening and regulating the vertical position of said first member, a partition extending transversely of said cylindrical member and dividing said chamber into upper and lower spaces, said partition carrying said seal means, said valve opening communicating with said upper space, and

metering passage means in said partition connecting said spaces for metering the flow from said upper space to said lower space.

2. A device according to claim 1 wherein said ground engaging portion includes a iiexible seal.

3. A device according to claim 1 wherein said valve means comprises a pair of cooperating elements each connected to one of -said cylindrical members.

4. A lifting device including first and second cylindrical members, said members being positioned in telescopic relation, said first cylindrical member including a top closure wall and thereby forming a chamber which is open at the bottom, seal means carried by one of said members and cooperating with the other of said members to prevent leakage therebetween, said second cylindrical member including a lower portion engaging a supporting surface, said second member being open at the bottom to said supporting surface, pressure means between said members for urging said members apart, means for con ducting said pressure means into said chamber, valve means included in said conducting means and having an opening, means operatively connected to said valve means responsive to the relative position of said members for varying said opening and regulating the vertical position of said iirst member, and a partition extending transversely of said second cylindrical member and dividing said chamber into upper and lower spaces, said valve opening communicating with said upper space, and a restricted metering passage means in said partition for metering iiow between said spaces.

5. A device according to claim 4 including iiuid passages in said valve whereby the pressure forces acting on said valve means are balanced.

6. A device according to claim 4 wherein said ground engaging portion comprises an inflatable seal for preventing escape of pressure from said lower space.

References Cited in the file of this patent UNITED STATES PATENTS 242,668 Male June 7, 1881 1,361,904 Rhodes Dec. 14, 1920 2,399,438 Johnson Apr. 30, 1946 2,743,787 Seck May l, 1956 2,918,183 Petersen et al Dec. 22, 1959 2,938,590 Barnett May 3l, i960 OTHER REFERENCES Publication: Science and Mechanics; .lune 1960; page 76. 

1. A LIFTING DEVICE INCLUDING FIRST AND SECOND CYLINDRICAL MEMBERS, SAID MEMBERS BEING POSITIONED IN TELESCOPIC RELATION, SAID FIRST CYLINDRICAL MEMBER INCLUDING A TOP CLOSURE WALL AND THEREBY FORMING A CLOSED CHAMBER WHICH IS OPEN AT THE BOTTOM, SEAL MEANS CARRIED BY ONE OF SAID MEMBERS AND COOPERATING WITH THE OTHER OF SAID MEMBERS TO PREVENT LEAKAGE THEREBETWEEN, SAID SECOND CYLINDRICAL MEMBER INCLUDING A LOWER PORTION ENGAGING A SUPPORTING SURFACE, SAID SECOND MEMBER BEING ALSO OPEN TO SAID SUPPORTING SURFACE, PRESSURE MEANS BETWEEN SAID MEMBERS FOR URGING SAID MEMBERS APART, MEANS FOR CONDUCTING SAID PRESSURE MEANS INTO SAID CHAMBER, VALVE MEANS INCLUDED IN SAID CONDUCTING MEANS AND HAVING AN OPENING, MEANS OPERATIVELY CONNECTED TO SAID VALVE MEANS AND RESPONSIVE TO THE RELATIVE POSITION OF SAID MEMBERS FOR VARYING SAID OPENING AND REGULATING THE VERTICAL POSITION OF SAID FIRST MEMBER, A PARTITION EXTENDING TRANSVERSELY OF SAID CYLINDRICAL MEMBER AND DIVIDING SAID CHAMBER INTO UPPER AND LOWER SPACES, SAID PARTITION CARRYING SAID SEAL MEANS, SAID VALVE OPENING COMMUNICATING WITH SAID UPPER SPACE, AND METERING PASSAGE MEANS IN SAID PARTITION CONNECTING SAID SPACES FOR METERING THE FLOW FROM SAID UPPER SPACE TO SAID LOWER SPACE. 